Readjustable Locking Plate Hole

ABSTRACT

A bone plate comprises a locking hole extending through the bone plate from a top surface to a bottom surface thereof. The locking hole is threaded and sized and shaped to lockingly receive a correspondingly threaded head of a bone fixation element therethrough. The bone plate further comprises a first plate relief extending at least partially through a thickness of the plate and separated from the locking hole to define a first weakened portion of the bone plate. The first plate relief extends around a portion of a circumference of the locking hole.

PRIORITY CLAIM

The present application claims priority to U.S. Provisional ApplicationSer. No. 61/177,423 entitled “Readjustable Locking Plate Hole” filed onMay 12, 2009 to Urs Hulliger and Tom Overes, the entire disclosure ofwhich is incorporated herein by reference.

BACKGROUND INFORMATION

The repositioning and proper alignment of bone fragments is essential toeffective bone fracture treatment and restoring proper bone length, axisand rotation. If fragments of the bone are misaligned force distributionacross the bone is compromised, increasing of the likelihood of furtherinjury due to excessive wear of joint surfaces, etc. resulting from thesub-optimal load distribution. Improper alignment of the bone may alsohave a significant impact on motion patterns of the bone and leave thebone more susceptible to further fracture.

SUMMARY OF THE INVENTION

The present invention is directed to a bone plate comprising a lockinghole extending through the bone plate from a top surface to a bottomsurface thereof, the locking hole being threaded and sized and shaped tolockingly receive a correspondingly threaded head of a bone fixationelement therethrough in combination with a first plate relief extendingat least partially through a thickness of the plate and separated fromthe locking hole to define a first weakened portion of the bone plate,the first plate relief extending around a portion of a circumference ofthe locking hole.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a first partial cross-sectional view of a bone plate holeaccording to a first embodiment of the invention;

FIG. 1B shows a top view of the bone plate hole of FIG. 1;

FIG. 2A shows a second partial cross-sectional view of the bone platehole of FIG. 1A after the position of a screw inserted therein has beenadjusted relative to its position in FIG. 1A;

FIG. 2B shows a top view of the bone plate of FIG. 1, in which theposition of the screw inserted therein has been adjusted as shown inFIG. 2A;

FIG. 3 shows a perspective view of a bone plate hole according to afirst alternate embodiment of the invention;

FIG. 4A shows a top view of a bone plate hole according to a secondalternate embodiment of the invention;

FIG. 4B shows a partial cross-sectional view of the bone plate hole ofFIG. 4A;

FIG. 5A shows a top view of a bone plate hole according to a thirdalternate embodiment of the invention;

FIG. 5B shows a partial cross-sectional view of the bone plate hole ofFIG. 5A;

FIG. 6A shows a first perspective view of a bone plate hole according toa fourth alternate embodiment of the present invention;

FIG. 6B shows a second perspective view of the bone plate hole of FIG.6A;

FIG. 6C shows a third perspective view of the bone plate hole of FIG.6A;

FIG. 7 shows a partial cross-sectional view of a bone plate holeaccording to a fifth alternate embodiment of the present invention;

FIG. 8A shows a first top view of a bone plate hole according to a sixthalternate embodiment of the present invention;

FIG. 8B shows a second top view of the bone plate hole of FIG. 8A;

FIG. 8C shows a partial cross-sectional view of the bone plate hole ofFIG. 8A;

FIG. 9A shows a partial cross-sectional view of a bone plate holeaccording to a seventh alternate embodiment of the present invention;

FIG. 9B shows a first top view of the bone plate hole of FIG. 9A;

FIG. 9C shows a second top view of the bone plate hole of FIG. 9A; and

FIG. 10 shows a partial cross-sectional view of a bone plate holeaccording to an eighth alternate embodiment of the present invention.

DETAILED DESCRIPTION

The present invention may be further understood with reference to thefollowing description and the appended drawings, wherein like elementsare referred to with the same reference numerals. The present inventionrelates generally to systems and methods for the fixation of fracturedor otherwise damaged bone. Specifically, the invention relates to a boneplate hole with a new compression relief eliminating the need for knownnon-locking compression holes (e.g., combination holes), as will bedescribed in more detail below. Specifically, conventional compressionholes engage screws inserted therethrough with an angled surface thatforces the screw axis in a particular direction as the screw is furtherdriven into the bone to apply compressive forces between bone fragmentscoupled to the plate. However, the angled surfaces and the movement ofthe head of the screw relative thereto do not permit the screw to belocked in position (e.g., threadedly engaged) in the bone plate. Theexemplary bone plate hole according to the present invention can lockthe screw to the plate while permitting minor adjustments in theposition/orientation of the screw relative to the plate to repositionbone fragments coupled thereto after the bone plate has been positionedand locked thereagainst. Specifically, plate holes according to thepresent invention permit a physician to pivot a bone screw afterinsertion into the bone to adjust the position of a portion of bonecoupled thereto, as will be described in greater detail hereinafter.Those skilled in the art will understand that, as used in thisapplication, the term top refers to a portion of the device which, in anoperative position, faces away from a bone to which it is being appliedwhile bottom refers to portions of the device which, in the operativeposition, face the bone.

As shown in FIGS. 1A-2B, a system 100 according to an exemplaryembodiment of the invention comprises a plate body 102 formed with aplate hole 104 extending therethrough from a top surface 106 to a bottomsurface 108. The plate hole 104 is substantially conical with its largerdiameter at the top surface. The taper angle of the plate hole 104 ispreferably in the range of 10° to 30°, wherein the upper limit indicatesa maximum lateral degree of movement of a bone screw 10 insertedtherethrough. However, as would be understood by those skilled in theart, any taper angle in the range of 0-90° may also be employed, whereinthe maximum taper angle is selected to maintain a head of the bone screw10 in a locked position within the plate. A compression relief 110 isformed on the plate body 102 adjacent the plate hole 104. Thecompression relief 110 extends into the plate body 102 by apredetermined depth. In an exemplary embodiment, the compression relief110 comprises an arced slot extending into the top surface along an arclength spanning at least half of the diameter of the plate hole 104. Inanother embodiment of the present invention, the compression relief 110may extend over an arc of approximately 90°-270° relative to the platehole 104, wherein a selected length depends on one or more of thematerial properties of the plate body 102 and an intended implantationsite within the living body. Specifically, when the plate body 102 ispositioned over a bone with a high density, the compression relief 110may have a greater arc length than when positioned over a bone with alow density, the increased length permitting greater force absorption bythe compression relief 110, as will be described in greater detailhereinafter. In the embodiment of FIGS. 1A-2B, the compression relief110 is substantially concentric with the plate hole 104 when in anunstressed state and extends around approximately one half of itscircumference to permit deflection of a bone screw 10 inserted throughthe plate hole 104 toward the compression relief 110. Accordingly, thecompression relief 110 is preferably positioned relative to the platehole 104 in a manner facilitating deflection of a portion of the platebody 102 between an edge of the plate hole 104 and the adjacent relief110 in a direction toward the relief 110. As shown below, compressionreliefs according to the invention may assume any of a variety of shapesand positions relative to the plate hole 104 and are not restricted tothe partial circumferential shape of the compression relief 110 of FIGS.1A-2B.

The plate body 102 may be made of any suitable material including, butnot limited to, a compound plastic, polyaryletheretherketone (“PEEK”),stainless steel, a cobalt chrome alloy, titanium, a titanium alloy,etc., as those skilled in the art will understand. The material selectedfor the plate body 102 must be biocompatible and must exhibit therigidity required to withstand the forces which will be exertedthereupon during and after attachment to a bone as would be understoodby those skilled in the art. The compression relief 110 serves to reducea rigidity of a portion of the plate body 102 adjacent to the plateholes 104 and, more specifically, of the portion of the plate body 102lying between the compression relief 110 and adjacent the plate hole104. Specifically, the compression relief 110 defines a reducedthickness portion 112 of the plate body 102 adjacent to the plate hole104 that is more flexible than portions of the plate body 102 adjacentto the plate hole 104 which are not surrounded by the compressionrelief. Thus, when a laterally directed force is applied to the platehole 104 via the bone screw 104, as will be described in greater detaillater on, the reduced thickness portions 112 deform toward the reliefs110 as shown in FIGS. 2A and 2B. A driver (not shown) configured toengage a respectively sized slot 14 on the head 12, is used to screw thebone screw 10 into the plate hole 104. As the tapered head 12 of thebone screw 10 advances into the plate hole 104 in the direction A, thehead 12 exerts an increasing amount of radially outwardly directed forceagainst the portion of the plate body 102 adjacent thereto. Theincreased force causes the reduced thickness portion 112 to deformmoving the portion of the plate hole 104 adjacent the top surface 106radially outward toward the relief 110, as shown in FIG. 2A.Specifically, the deflection causes the screw axis to move in thedirection B to generate a compressive force between the bone fragmentinto which the screw 10 has been driven and an adjacent bone fragment(not shown) immediately to the right thereof (as seen in FIG. 2A).Deformation of the compression relief 110 also absorbs some of thepressure exerted by the screwing of the bone screw 10 during insertion.The inner surface of the plate holes 104 may be threaded to lock thescrews 10 in place therein.

FIG. 3 depicts a system 200 according to another embodiment of thepresent invention. The system 200 is formed substantially similarly tothe system 100 with the exception of a compression relief 210 whichextends entirely through plate body 202 so that the portions of theplate body 202 surrounding plate holes 204 are coupled to the rest ofthe plate body only at bridge portions 212 formed around a portion ofthe circumference of the plate holes 204 not surrounded by thecompression reliefs 210. In an exemplary embodiment, the compressionrelief 210 is substantially concentric with the plate hole 204 andextends around more than one half of the circumference of the plate hole204. In an alternate embodiment, the compression relief 210 may extendacross any portion of a circumference of the plate hole 204. Asdescribed in greater detail above, the location of the compressionrelief 210 relative to the plate hole 204 determines a deflectiondirection of a bone screw inserted into the plate hole 204. A reliefslit 214 may be formed through the material surrounding the plate hole204 diametrically opposed to the bridge portion 212 to permit the holeto be enlarged slightly as the screw 10 is inserted thereinto. It isnoted, however, that the relief slit 214 may be oriented in anydirection desired without deviating from the spirit and scope of thepresent invention. In a first configuration, walls of the bridge portion212 adjacent to the relief slit 214 are in contact with one another whenthe plate hole 204 is in an unstressed state. When a radially expansivepressure is applied thereto during the insertion of a bone screw 10, therelief slit 214 expands deforming the bridge portion 212 and thecompression relief 210.

As shown in FIGS. 4A-4B, a system 300 according to another embodiment ofthe invention includes a plate body 302 with a plate hole 304substantially similar to the plate hole 204 of FIG. 3 except that thecompression relief has been separated into first and second compressionreliefs 310, 312 each bordering a periphery of the plate hole 304. Thefirst and second compression reliefs 310, 312 which extend through theplate body 302 from a top surface 306 to a bottom surface 308. Similarto the compression relief 210 of FIG. 3 each of the first and secondcompression reliefs 310, 312 extend along an arc portion 314 to alongitudinal portion 316 extending away from the plate hole 304 by apredetermined length. The longitudinal portions 316 of each of the firstand second compression reliefs 310, 312 are parallel to one another andseparated from one another by an extension 318 of the plate hole 304abutting radially outward from the plate hole 304 a predetermineddistance substantially similar to a length of each of the longitudinalportions 316.

The extension 318 allows for the radial expansion of the plate hole 304in a manner similar to the relief slit 214 while the first and secondcompression reliefs 310, 312 allow for movement of the head of a bonescrew 20 in the direction of the arrow C. Specifically, as the bonescrew 20 is being inserted into the plate hole 304 and threadedly lockedtherein, pressure may be applied to the periphery of the plate hole 304to deform the material between the compression reliefs 310, 312,rotation of the screw 20 causing a top surface of the head thereof todeflect laterally in the direction of the arrow C while the shaft of thescrew 20 deflects laterally in the direction D. Thus, the screw 20assumes an angle within the bone that is not perpendicular to the planeof the plate body 302. Accordingly, the longitudinal portions 316 andthe extension 318 may be selectively angled and positioned to permitmovement of the bone screw 20 in a desired direction of the plate body302, as those skilled in the art will understand.

In yet another embodiment of the present invention, as shown in FIGS. 5Aand 5B, a system 400 may be formed substantially similarly to the system300 of FIGS. 4A-4B with the exception of an additional driver hole 420formed on a side of the plate hole 304 substantially opposite a desireddirection of movement of the bone screw 20. Specifically, as discussedearlier, the compression reliefs 310, 312 allow the plate body 302 to bedeformed so that the head of the bone screw 20 may be moved toward thelongitudinal portions 316 and extension 318 of the compression reliefs310, 312. The driver hole 420 includes a substantially conical, threadedfirst portion 424 sized to receive a correspondingly shaped conical bolt32 with an arced slot 422 extending on either side of this first portion424. After the screw 20 has been inserted through a plate hole 304 intothe bone, its position may be adjusted by rotating the conical bolt 32to draw it further through the first portion 424 of the driver hole 420toward the top surface of the plate body 302. This brings increasinglylarger portions of the conical bolt 32 into the driver hole 420deforming the portion of the plate body 302 between the driver hole 420and the plate hole 304 and forcing the head of the screw 20 to move awayfrom the driver hole 420 in a manner similar to that described above.The driver hole 420 is preferably substantially centered with respect toa desired direction of movement of the bone screw 20.

As shown in FIGS. 6A-6C, a system 500 according to another embodiment ofthe invention includes a compression relief 510 of a bone plate 502configured to allow a user to select a direction of movement of a bonescrew 30 inserted therethrough. The plate hole 504 and compressionrelief 510 are formed substantially similarly to the plate hole 104 andcompression relief 110 of FIGS. 1A-2B while the portion of the platebody 502 remaining between the plate hole 504 and the compression relief510 includes a first recess 512 including threading on both inner andouter walls of the compression relief 510. The first recess is sized andshaped to engage a substantially conical spacer 516 therein to lock theplate hole 504 in the neutral position (i.e., the position it remains inwhen unstressed). Insertion of a spacer 516 into the first recesses 512prevents the deformation of the plate hole 504 and a screw 20 thereinaway from a neutral position.

The plate hole 504 also includes a plurality of second recesses 518distributed about the circumference of the plate hole 504. The secondrecesses 518 include conical threaded portions on the inner wall of thecompression relief 510 (i.e., the portion of the plate body 502 betweenthe plate hole 504 and the compression relief 510) but the adjacentportions of the outer wall of the compression relief 510 are notrecessed. Specifically, since the size of the opening defined by eachsecond indentation 518 is smaller than a diameter of the spacer 516, thespacer 516 applies a compressive force to the plate hole 504 duringinsertion. The conical shape of the spacers 516 permits the applicationof increasing compressive force as the spacer 516 is screwed furtherinto the second indentations 518. In a preferred method according to thepresent invention, a user may screw a spacer 516 into a selected one ofthe first or second indentations 512, 518 to permit biasing of the bonescrew 30 in an opposite direction, as described earlier. Thus, insertionof a spacer 516 into one of the second recesses 518 deforms the platebody 502 pushing the plate hole 504 and the screw 20 therein away fromthe spacer 516. The distribution of second recesses 518 around thecircumference of the plate hole 504 allows a user to select a directionof compression to be applied. Those skilled in the art will understandthat the recesses 512 may be distributed about the circumference of theplate hole 504 in any desired pattern to facilitate the application ofcompressive forces in the desired directions.

FIG. 7 depicts a system 600 according to yet another embodiment of thepresent invention. The system 600 is formed substantially similarly tothe system 100 with the exception of a compression portion 610positioned adjacent a plate hole 604 extending through a plate body 602.Specifically, instead of a compression relief extending partially orcompletely through the plate body 602, the compression portion 610 isprovided in a region bordering the compression hole 604 in the samemanner as the compression relief 110 of FIG. 1. The compression portion610 is formed of a material with a substantially lower density than theplate body 602, thus permitting compression thereof and allowing thedeflection of a bone screw 60 in a direction approaching the compressionregion, as described in greater detail earlier. An exemplary materialfor the compression portion 610 is one of a meshed metal or anothermaterial with high porosity. The exemplary embodiment of the presentinvention permits lateral movement and locking of the bone screw 60within the plate body 602 in the same manner as the system 100 whilealso preventing tissue ingrowth into the plate body 602, as thoseskilled in the art will understand. Those skilled in the art willunderstand that the compression portion 610 may be shaped and located inthe same manner as any of the compression reliefs described above or inany other suitable fashion without deviating from the scope of theinvention.

FIGS. 8A-8C depict another embodiment of the present invention, whereina system 700 comprises a plate body 702 having a plate hole 704extending therethrough, the plate hole 704 receiving a compressioninsert 710. The plate hole 704 is substantially cylindrical and extendsfrom a top surface 706 to a bottom surface 708 with a hole axis of theplate hole 704 being, for example, substantially perpendicular to alongitudinal axis of the plate body 702. The plate hole 704 furthercomprises a recess 718 extending into a wall thereof, for example,substantially equidistant from the top and bottom surfaces 706, 708,respectively, of the plate body 702. The recess 718 is sized and shapedto rotatably engage a circular flange 720 of the compression insert 710,which may be positioned therein during manufacturing. The compressioninsert 710 is concentrically received within the plate hole 704 so thatan axis of an opening 716 extending through the compression insert 710is aligned with the plate hole 704 axis. The opening 716 through thecompression insert 710 comprises a first conical portion 712 extending apredetermined distance from the proximal surface 706 and a secondcylindrical portion 714 extending from the first conical portion 712 tothe distal surface 708. The second cylindrical portion 714 may bethreaded to permit screwing of a bone fixation element (not shown)thereinto.

A top surface 722 of the compression insert 710 has a substantiallycircular cross-section with the opening 716 extending through a centerthereof. A compression relief 724 extends into the top surface 722 alongan arc length spanning, for example, half of the diameter of the platehole 704 or more. It is noted, however, that the compression relief 724may extend over any portion of the plate hole 704 without deviating fromthe scope of the present invention. The compression relief 724 furtherdefines a bridge portion 726 extending around a portion of thecircumference of the plate hole 704 surrounded by the compression relief724, the bridge portion 726 comprises a reduced thickness portion of thetop surface 722. Unlike the compression reliefs discussed in earlierembodiments, the compression relief 724 may be crescent-shaped with anon-uniform thickness. A relief slot 728 may be formed in the topsurface 722 extending through the bridge portion 726 connecting theopening 716 to the compression relief 724. Like the relief slit 214 ofthe system 200, the relief slot 728 is configured to permit the opening716 to be enlarged slightly as the bone screw (not shown) is insertedthereinto. As a radially expansive pressure is applied thereto duringthe insertion of a bone screw into the fist conical portion 712, therelief slot 728 expands, deforming the bridge portion 726 and thecompression relief 724. The expansion allows a head of the bone screw tomove in the direction E. The exemplary embodiment of the presentinvention permits a physician or other user to rotate the compressioninsert 710 before or after the plate body 702 has been placed on atarget implantation site to select a direction E of movement of a bonescrew (not shown) inserted therethrough, as shown in FIGS. 8A and 8B toselect a resultant force on the plate body 702 as will be understood bythose skilled in the art. An exemplary method for the system 700 issubstantially the same as discussed in earlier embodiments. Once thebone screw has been screwed into the opening 716, lateral movement ofthe bone screw in the direction E prevents further rotation of thecompression insert 710.

As shown in FIGS. 9A-9C, a system 800 according to a further embodimentof the invention comprises an insert 810 formed substantially similarlyto the insert 710 of FIGS. 8A-8C with the exception of the dimensionsand mechanical properties thereof. Specifically, the insert 810 isinserted into a plate hole 804 extending through a plate body 802. Agroove 818 formed on an outer wall of the insert 810 is configured torotatably engage a flange 820 extending from a wall of the plate hole804. The groove 818 is formed with dimensions that permit looseengagement with the flange 820 sufficient to permit the insert 810 fromsliding out of engagement with the plate body 802 while also permittingrotation relative to the plate body 802 and a degree of lateral andlongitudinal movement of the insert 810 relative to the plate body 802.Specifically, the insert 810 is sized and shaped such that, wheninserted within the plate hole 804, a gap with a length A is formedbetween the plate hole and the insert 810, as shown in the top view ofFIG. 9B. A length of the groove 818 is therefore at least larger thanthe length A to prevent the insert 810 from sliding out of the platehole 804. One or both of the groove 818 and the flange 820 comprises agrooved or etched surface to increase friction therebetween. The insert810 further comprises a substantially conical opening 816 extendingtherethrough from a proximal surface 806 of the plate body 802 to adistal surface 808, dimensions of the conical opening 816 beingconfigured to match those of the head of a bone screw (not shown) to beinserted therethrough. An outer diameter of a proximal portion 814 ofthe insert 810 is selected to be smaller than a diameter of the platehole 804 to define a substantially symmetrical annular space 822therebetween. The reduction in diameter weakens the proximal portion 814so that the proximal portion 814 is deflectable into the empty space 822when subjected to a pressure by the head of a bone fixation element 80.A distal portion 816 of the insert 810 has a diameter sufficient topermit rotatable insertion thereof into the plate hole 804 with aminimal amount of lateral movement. Furthermore, the conical opening 816may be threaded to engage threads on the head of the bone screw.

In accordance with an exemplary method for the system 800, the bonefixation element 80 is inserted into the opening 816, wherein the insert810 is positioned within the plate hole 804. For example, the insert 810may initially be centered within the plate hole 804. After the bonefixation element 80 has been inserted therethrough to a predetermineddepth, the bone fixation element 80 and insert 810 may be biased along aside of the plate hole 810 so that, for example, a length 2A remains onthe opposite side thereof In this position, a longitudinal axis of thebone fixation element 80 is deviated from a longitudinal axis of theplate hole 804. Furthermore, pivoting of the bone screw in theaforementioned manner locks a position thereof within the bone in thesame manner as described in earlier embodiments. Specifically, as thehead of the bone fixation element 80 is screwed distally into theopening 816, radially outwardly directed pressure is applied by the headon the insert 810 causing the proximal portion 814 to deflect radiallyoutward into the annular space 822 in the direction F. Specifically, theproximal portion 814 expands radially outward upon receipt of thepressure from the bone fixation element 80. The deflection causes theproximal portion 814 to apply a constrictive pressure on the flange 820to lock the bone fixation element 80 within the plate hole 804 and alsoprevent rotation of the insert 810. Thus, this embodiment permits a userto pivot the bone screw (not shown) in any direction within the platehole 804.

As shown in FIG. 10, a system 900 according to another embodiment of theinvention is formed substantially similarly to the system 800 exceptthat an insert 910 is formed of first and second parts 910′, 910″cooperating to function in the same manner described above for thesystem 800. Furthermore, the insert 910 does not comprise an annularspace extending around a proximal portion thereof. The combined firstand second parts 910′, 910″ form an opening 916 substantially similar tothe opening 816. The second insert 910″ comprises a flange groove 918configured to engage a flange 920 of a plate body 902. An exemplarymethod for the system 900 is substantially similar to the methoddiscussed above with respect to FIGS. 9A-9C, wherein a compressive forceapplied by the first and second inserts 910′, 910″ on the flange 920locks a position of a bone screw and prevents further rotation of thefirst and second inserts 910′, 910″ relative thereto.

In an alternate embodiment of the present invention, each of the plateholes and respective compression reliefs may be formed of any shapeknown in the art. Furthermore, additional or lesser compression reliefsmay be employed without deviating from the scope of the presentinvention. In another embodiment (not shown), the compression relief ofthe present invention may be used in a bone plate with a variable angleplate hole, as those skilled in the art will understand.

It will be apparent to those skilled in the art that various othermodifications and variations may be made in the structure and themethodology of the present invention, without departing from the spiritor scope of the invention. Thus, it is intended that the presentinvention cover modifications and variations of the invention providedthat they come within the scope of the appended claims and theirequivalents.

1. A bone plate, comprising: a locking hole extending through the boneplate from a top surface to a bottom surface thereof, the locking holebeing threaded and sized and shaped to lockingly receive acorrespondingly threaded head of a bone fixation element therethrough;and a first plate relief extending at least partially through athickness of the plate and separated from the locking hole to define afirst weakened portion of the bone plate, the first plate reliefextending around a portion of a circumference of the locking hole. 2.The plate of claim 1, wherein the first plate relief is a recessextending partially through the bone plate and the first weakenedportion is between the locking hole and the first plate relief.
 3. Theplate of claim 2, wherein the first plate relief extends from the topsurface of the plate to a predetermined depth therein and wherein thefirst plate relief extends along a portion of a circle substantiallyconcentric with the locking hole.
 4. The plate of claim 1, wherein thefirst plate relief extends through the plate body to open to the topsurface and the bottom surface.
 5. The plate of claim 4, wherein thefirst plate relief extends around a portion of a circumference of thelocking hole so that a portion of the plate surrounding the locking holeis coupled to a remainder of the plate only by a bridge portionseparating ends of the first relief from one another, the bridge portionforming the first weakened portion.
 6. The plate of claim 1, wherein thelocking hole is threaded and substantially conical with a diameterthereof at the top surface greater than a diameter thereof at the bottomsurface.
 7. The plate of claim 1, further comprising a slot extendingfrom the locking hole to the first plate relief to define a direction ofdeflection of the locking hole.
 8. The plate of claim 1, furthercomprising a second plate relief separated from the first plate reliefto define a second weakened portion of the bone plate therebetween,wherein the first and second plate reliefs border portions of thecircumference of the locking hole and are located on sides of thelocking hole opposite from one another.
 9. The plate of claim 8, whereinthe first and second plate reliefs further comprise respectivelongitudinal hole portions extending away from the locking hole todefine a direction of deflection of the bone screw.
 10. The plate ofclaim 9, further comprising a third plate relief open to the lockinghole, the third plate relief extending substantially parallel to andbetween the longitudinal hole portions, the third plate relief openinginto the locking hole.
 11. The plate of claim 10, wherein the lockinghole is sized such that insertion of a bone screw thereinto exerts acompressive force on the first and second plate reliefs to causemovement of the bone screw in desired direction and an expansion of thelocking hole.
 12. The plate of claim 10, further comprising a fourthplate relief located opposite a location of the third plate relief andconfigured to lockingly receive a spacer therein, the fourth platerelief being shaped so that, as a spacer is inserted therein, anoutwardly directed force increases moving the locking hole toward thethird plate relief.
 13. The plate of claim 5, further comprising a firstrecess in a portion of the plate surrounding the locking holediametrically opposed to the bridge portion and a second recess formedin a portion of the plate forming a radially outer wall of the firstplate relief aligned with the first recess, insertion of a spacer intothe first and second recesses locking the locking hole in a neutralposition and preventing deflection of the locking hole.
 14. The plate ofclaim 13, further comprising a third recess in a portion of the platesurrounding the locking hole adjoining the first plate relief andseparated from the first recess around the circumference of the lockinghole, the third recess sized and shaped so that, upon insertion of aspacer therein, the locking hole is deflected away from the neutralposition in a direction diametrically away from the third recess. 15.The plate of claim 14, further comprising a fourth recess in a portionof the plate surrounding the locking hole adjoining the first platerelief and separated from the first and third recesses around thecircumference of the locking hole, the fourth recess sized and shaped sothat, upon insertion of a spacer therein, the locking hole is deflectedaway from the neutral position in a direction diametrically away fromthe fourth recess.
 16. The plate of claim 1, wherein the first platerelief comprises a first material more compressible than a secondmaterial of which portions of the bone plate extending therearound areformed.
 17. The plate of claim 16, wherein the first material includesone of a meshed material and a metal with a porosity higher than that ofthe second material.
 18. A bone plate, comprising: a bone fixationelement hole extending through the bone plate from a top surface to abottom surface thereof; an insert rotatably received within the bonefixation element hole, an opening extending through the insert beingsized and shaped to receive a head of a bone fixation elementtherethrough; and a first plate relief extending at least partiallythrough a thickness of the insert to define a first weakened portion ofthe insert, the first plate relief extending around a portion of acircumference of the insert.
 19. The plate of claim 18, wherein thefirst plate relief extends from the top surface of the insert to apredetermined depth therein and wherein the first plate relief extendsalong a portion of a circle substantially concentric with the lockinghole.
 20. The plate of claim 19, wherein the locking hole comprises agroove extending into a wall thereof configured to engage a flangeextending from an outer periphery of the insert.
 21. The plate of claim19, wherein a portion of the insert bordering the first plate relieflocking hole forms a bridge portion defining weakened portions of theinsert deflectable under pressure from a bone fixation element.
 22. Theplate of claim 21, further comprising a slot extending from the firstplate relief to the opening of the insert, a direction of the slotdefining a direction of deflection of the opening.
 23. The plate ofclaim 18, wherein the opening extending through the insert issubstantially conical with a diameter thereof at the top surface greaterthan a diameter thereof at the bottom surface.
 24. The plate of claim18, wherein the first plate relief is formed as a groove extendingaround a portion of a periphery of the insert.
 25. The plate of claim24, wherein the first plate relief is configured to engage a flangelocated on a wall of the locking hole.
 26. The plate of claim 24,wherein the weakened portion of the insert is configured to deflectradially outward when a bone screw is inserted thereinto to apply aconstrictive pressure on the flange.
 27. The plate of claim 26, whereinthe insert is formed of multiple elements insertable into the lockinghole.
 28. A method for readjusting a bone fixation element in a boneplate, comprising: inserting a bone fixation element into a holeextending through a bone plate and into a target portion of bone, thebone plate including a plate relief weakening a first portion of theplate; and after inserting the bone fixation element into the hole,deforming a portion of the plate adjacent to the hole to move the holetoward the plate relief to apply a compressive force to the targetportion of bone and an abutting portion of bone to which the plate iscoupled.
 29. The method of claim 28, wherein the portion of the plateadjacent to the hole is deformed by inserting a first spacer into afirst spacer opening in the plate to apply a force from the openingtoward the plate relief.
 30. A method for readjusting a bone fixationelement in a bone plate, comprising: inserting a bone fixation elementinto an insert hole of an insert rotatably positioned within a holeextending through a bone plate and into a target portion of bone, theinsert including an insert relief weakening a first portion of theinsert; and after inserting the bone fixation element into the inserthole, deforming a portion of the insert to move the first portion of theinsert to a deflected position, the deformation applying a compressiveforce to the target portion of bone and preventing rotation of theinsert relative to the locking hole.